Process of manufacturing dried yeast.



No Drawing.

PETER DIEDRIGH HINRICH OHLHAVER, OF SAN'DE, GERMANY.

PBQCESS OF MANUFACTURING DRIED YEAST.

Specification of Letters latcnt.

Application filed August 24, 1911. Serial No. 645,829.

Patented Mar. 12,1912.

To all whom it mag concern: 7,

Be it known that 1, PETER Dmomon HIN- 'RICH OHLHAVER, a subject of theEmperor of Germany, residing at Sande, Germany, have invented certainnew and useful Improvements in Processes of Manufacturing Dried Yeast,of which the following is a specification.

This invention relates to a process of manufacturing dried yeast bywhich the yeast undergoes a preliminary maturing operation before beingsubmitted to the drying process, and has for its object to retam thefull vitality of the yeast and as a consequence its maximum raisingpower.

Yeast is a fungus of mlcrosco ical size, which can be cultivated, and onthis account has become of eminent importance in connection with theroduction of spirits and beer, and for all kinds of baking purposes.Yeast is mostly supplied to users, especially for baking purposes, incompressed condition but is liable to deteriorate after a very shorttime, in consequence of which attempts have been made to reserve it bdrying but hitherto with litti is quitepossible to dry the yeast, butdur ing the drying process the vitality of the yeast destroyed, andconsequently dried yeast has relatively a very small raising ower. v

All attempts to dry the yeast without injuring its life have ithertofailed because the yeast has not first been brought to a proper state ofmaturity for the act of a drying.

Yeast consists mainly of albuminous substances, carbohydrates, fats, andsalts. In the fresh yeast these substances appear in forms which do notpermit of the drying of the yeast without great injur to it. Only afterthe yeast has been sub ected to treatment causin a transformation ofthese substances, whic brings them to a special maturity for dryingpurposes are the roper conditions for the application of a rylng esuccess. t.

the zymase ferments the lower kinds producing alcohol and carbonic acid.As con cerns the life of the yeast however the two other enzymes, theoxydase and the peptase are the most important. The peptase provides theyeast with its principa ingredient, namely; difi'usible albumin, and theoxydase builds up from the diffusible albumin thus supplied the lifepreserving plasma albumin, the organized albumin from which undernormal. conditions of development the young cell is created.Simultaneously the oxydase causes the necessary respiration to give anactive building up of the organism, and for this respiration, partly oxyn from the air dissolved in the water is mployed, and partly oxygenderived from certain chemlcal combinations.

In order to attain the state of maturity necessary to successfully ap lythe drying process above referred to tl ie building up element 2. e.theoxydase, must be stren hened as much as possible so as to enab e 1tto transform the .reserve albumin and to expel, by respiration, theother less important reserve substances.

The state of maturity necessary for the purpose of drying is reachedwhen the re-.-

serve albumin in the yeast cell has been ontirely, or almost entirely,transformed into plasmatical albumin.

. The oxydase requires oxygen for its building u activities, and isconsiderably strengt ened if it can absorb large quantn ties of thatelement. Oxydase absorbs oxygen from water with especial ease and greatadvantage, consequentl water may be said to be a necessary ingre ientfor the develop- 95 All the conditions necessary to bring:

ment of yeast;

yeast to the maturity necessary for the drying process will be presentif the yeast is finely distributed in waterthrough which air is passing,as by this disposit on abundantquantities of oxygen forthegitra'nsformation processes of t e oxydase are. read ly obtainable.The yeast thus finely d1Str1buted in water is so to speak washed theair, and the o dase being thus actuated to give very active respirationis thereby strengthened. The res iration at the same I time expels apart of e reserve substances buttransforms the reserve albumin into thelife preserving plasma albumin and thus brings about the required-stateof maturity for the drying process.

Towhat extent the ripe state of maturity is brought about quickly, orotherwise, depends partly upon the whole constltutlon of the yeast cellwhich is subject to considerable fluctuations, and partly upon thequantlty of-reserve substances contained in the yeast cells which haveeither to be transformed,

or expelled by respiration' In' some cases the necessary degree ofripeness was obtained in a few hours, in other cases the treatmentrequired about 7 0 hours; in mostby the continuous passa e of air,favors at the same time the'desire transformation of the substanceswithin the yeast cell.

Small additions of any form of sugar, or sugary combinations, to thewater in which the air-washing of the yeast takes place, are ofadvantage. The sugar renders it easier for the oxydase to build up theplasma albumin, simultaneously influencing in an active manner the sugartransforming organ of the yeast; namely, the zymase. Starch also actsadvantageously, or still better, substances which contain starch inlarge quantities, such as flour, malt, pulverized bread, and the like,when added to the water in which the yeast is being washed with air, oralternatively the. air-washed yeast may be mixed with these substances.The yeast is then dried together with such substances.

The influence which the state of maturity of the yeast thus obtainedexercises upon the drying is best shown by a few examplesz A normalpressed yeast, as heretoforeaus'ed' in the trade, possessed while in thefresh condition a raising power of 710 c.cm. This fresh yeast wascarefully dried in an air current and the dried yeast thus obtained hada raising power of 185 0.0m,v The same fresh yeast was subsequentlybrought first to the state of maturity for'th'e-drying process as setout herein, and then dried 1n the usual manner by the air current, andthis dried yeast had a raislng power of 2595 com. or equlvalent to araising power 14 times as large as the dried east to which the stateofmaturity had not een imparted.

Another commercial fresh yeast raised 870 c.cm.; in a dried statewithout the ripening treatment 420 c.cm.; but by applying the 1. Theherein described process of manu-.

facturing dried yeast, which consists in subject-ing the fresh yeast toa maturing treatment with water containing air for asufficient time totransform the reserved albumin of the yeast cells. into plasma albumin,and then drying such matured yeast.

2. The herein describedprocess of manufacturin dried yeast, whichconsists in subjecting t e fresh yeast to a maturing treatment 'withaerated water and a carbohydrate, and then drying such matured yeast.

3. The herein described process of manufacturing dried yeast, whichconsists in subjecting the fresh yeast to a maturing treatment withaerated water and a product containing starch, and then drying suchmatured yeast.

4. The herein described process of manufacturing driedj yeast, whichconsists in sub-- jecting the fresh yeast to a maturing treatment with,aerated Water and an excess of a carbo-hydrate, and then drying suchma-' tured yeast and the excess carbo-hydrate.

5. The herein described process ofmanufacturing dried yeast having anaugmented raising power, which consists in oxygenating the fresh yeastto transform the reservedalbumin of the yeast cells into plasma.albumin, continuing such treatment for storing oxygen in the oxydase ofthe yeast, and then drying the yeast.

In testimony whereof I have affixed my signature in presence of twowitnesses.

PETER DIEDRICH HINRIOH OHLHAVER.

Witnesses: .EnNEs'r H. L. MUMMENHOFF, IDA CHRIST. HAFERMANN.

